<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <link rel="stylesheet" href="./styles/index.css" />
  <title>Document</title>
</head>

<body>
  <div id="app" class="score-case">
    <div class="table">
      <table>
        <thead>
          <tr>
            <th>编号</th>
            <th>科目</th>
            <th>成绩</th>
            <th>操作</th>
          </tr>
        </thead>
        <tbody>
          <tr v-for="({id,subject,score},index) in list" :key="id">
            <td>{{index+1}}</td>
            <td>{{subject}}</td>
            <td class="red">{{score}}</td>
            <td><a href="#" @click="del(id)">删除</a></td>
          </tr>
          <!-- <tr>
              <td>2</td>
              <td>英语</td>
              <td>80</td>
              <td><a href="#">删除</a></td>
            </tr>
            <tr>
              <td>3</td>
              <td>数学</td>
              <td>100</td>
              <td><a href="#">删除</a></td>
            </tr> -->
        </tbody>
        <tbody>
          <tr>
            <td colspan="5">
              <span class="none" v-if="list.length<=0">暂无数据</span>
            </td>
          </tr>
        </tbody>

        <tfoot>
          <tr>
            <td colspan="5">
              <span>总分：{{total}}</span>
              <span style="margin-left: 50px">平均分：{{total/list.length}}</span>
            </td>
          </tr>
        </tfoot>
      </table>
    </div>
    <div class="form">
      <div class="form-item">
        <div class="label">科目：</div>
        <div class="input">
          <input type="text" placeholder="请输入科目" v-model="subject" />
        </div>
      </div>
      <div class="form-item">
        <div class="label">分数：</div>
        <div class="input">
          <input type="text" placeholder="请输入分数" v-model="score" />
        </div>
      </div>
      <div class="form-item">
        <div class="label"></div>
        <div class="input">
          <button class="submit" @click="add">添加</button>
        </div>
      </div>
    </div>
  </div>
  <script src="https://cdn.bootcdn.net/ajax/libs/vue/2.7.14/vue.js"></script>

  <script>
    const app = new Vue({
      el: '#app',
      data: {
        list: [
          { id: 1, subject: '语文', score: 20 },
          { id: 7, subject: '数学', score: 99 },
          { id: 12, subject: '英语', score: 70 },
        ],
        subject: '',
        score: ''
      },
      methods: {
        del(id) {
          this.list = this.list.filter(item => item.id !== id)
        },
        add() {
          this.list.unshift({
            id: +new Date(),
            subject: this.subject,
            score: +this.score
          })
          this.subject = '',
            this.score = ''
        }
      },
      computed: {
        total() {
          return this.list.reduce((prev, { score }) => prev + score, 0)
        }
      }
    })
  </script>
</body>

</html>